Nipple



FIG. 1 is a perspective view of a nipple, showing our new design;

FIG. 2 is a front view of the nipple of FIG. 1; and,

FIG. 3 is a top view of the nipple of FIG. 1.

The broken line showing in FIGS. 1 through 3 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a nipple, as shown and described. 